The community mental health and deinstitutionalization movements have made the general hospital psychiatric emergency room the focal point of the local mental health system. Its professionals are called upon to absorb the burden of containing and defining the unmanageable emotional turmoil of the patient and are most frequently the initiators of the civil commitment process. The objective of this study is to develop an index which validly reflects how psychiatric emergency room admission personnel use statutory guidelines of dangerousness and grave disability due to mental disorder in the involuntary hospitalization of the mentally ill. Based on a review of standard practice texts, research efforts, legal guidelines in the California Welfare and Institutions Code, and observations of admission procedures in a psychiatric emergency room, we will develop an index of the extent to which a patient can be described as dangerous and/or gravely disabled. The index will be comprised of an inclusive set of indicators of these statuses scaled according to severity. Observations of the assessment of dangerousness and grave disability by mental health personnel working in a psychiatric emergency room will be completed in three phases leading to the development of an index which is inclusive, practical, and reliable. Case vignettes will be developed that reflect index scores and the reliability of trained social work students' ratings of the vignettes using the index will be determined. The validity of the index will be determined in a survey of psychiatric emergency room admission personnel whose "blind" rank ordering of the severity of dangerousness and/or grave disability reflected in the case vignettes will serve as the validation criterion. Ultimately, we plan to use the index as a training device and evaluate its effectiveness in a larger experimental study of the relationship between dangerousness and grave disability and other factors which influence the admission of an involuntary patient.